Digital corrections: It's the result that counts

[gzost]

I've been interested in personal audio for a while, but I only entered full-blown headphone hobby mode about a year ago.

I'm a strong objectivist regarding audio, i.e. we may not be able to completely predict the sound of headphones from measurements, but that is a problem of insufficient measurements, not magic.

My ideal headphones do not have a signature, but are neutral (yes, neutral here is something which in its details is up for discussion). Neutral to me at least means: a set of headphones works equally well across all music genres.

This also means that I'm interested in the overall result, i.e. what reaches my ears, and I'm not ideological about how this is achieved.

I've tried quite a few headphones and in ears, and while there are some I really like or liked (Shure SE535, Fostex TH-x00, Sennheiser IE80), they all are compromises in some way.

We live in the digital age, and digital sound processing should be part of the process where useful. In my experience, digital correction of frequency response is falls into that category.

A classic EQ (e.g. equalizer APO on windows) is a good start, but may be limited (# of bands) and requires a lot of work.

I'm interested in the dedicated headphone correction software that is starting to appear. The one I've tried so far (Sonarworks True-Fi) has been transformative on some headphones, and an improvement on all.

As an example, the very comfortable, but otherwise decidedly lackluster Sennheiser HD598 all of a sudden has bass, and the maddening inconsistencies in the treble are gone.

I'm excited by what is happening in this space, and I'm looking forward to more solutions like this. Ideally, digital correction for headphones should be an integrated part of the playback chain, with all headphones either coming with (ideally individual) measurements to use in the correction, or in the case of integrated amping with the correction built in.

Im also looking forward to the next steps: Correcting not just for frequency response, but also adapting to the shape of the ears and individual hearing perception. (I'm seriously considering getting a pair of Nuraphones, since these seem to be among the most advanced on this path.)

What developments in the area of personal audio do you see as interesting, promising and exciting?

(I am in not way affiliated with True-Fi or Nuraphone, and have no financial interest in promoting their products. I like True-Fi with various supported headphones I own, and have found reports on Nuraphone interesting.)

 

[ProtegeManiac]

My ideal headphones do not have a signature, but are neutral (yes, neutral here is something which in its details is up for discussion). Neutral to me at least means: a set of headphones works equally well across all music genres.

Technically, neutral would mean it doesn't modify the signal, which means a totally flat response. Problem is, that doesn't exist yet, not even for the bulk of the audible range at 20hz to 10,000hz.

What people are debating isn't neutrality in the absolute sense but which compromise they can make on what is subjectively closer to neutral.

I've tried quite a few headphones and in ears, and while there are some I really like or liked (Shure SE535, Fostex TH-x00, Sennheiser IE80), they all are compromises in some way.

It will be that way until driver designs can be perfectly flat from 20hz to 10,000hz at least, let alone all the way to 20,000hz.

A classic EQ (e.g. equalizer APO on windows) is a good start, but may be limited (# of bands) and requires a lot of work.

I'm interested in the dedicated headphone correction software that is starting to appear. The one I've tried so far (Sonarworks True-Fi) has been transformative on some headphones, and an improvement on all.

As an example, the very comfortable, but otherwise decidedly lackluster Sennheiser HD598 all of a sudden has bass, and the maddening inconsistencies in the treble are gone.

The thing is though it's actually easier to work with all those variables and still get a smoother sound overall despite having a limited number of EQ bands. 31bands isn't even all that limited - I have a bigger problem with not being able to tweak the Q-factor. You just start with several measurements of hte headphone and figure out where it has peaks and then flatten them; maybe bring up the low bass just to get a bit lower before the -3dB point so you get more extension without forcing the drivers to work hard.

Other correction software try to do sound tests to minimize variances between each driver that comes out of the factory, but the problem with these is that they actually have even less control bands and are not as precise.

Samsung's Adapt Sound for example will run sine beeps and only ask if you can hear the beep. It can't distinguish between a peak, ie, a very loud beep. and a weaker one. All it does is boost what you can't hear or barely hear but tell it you can't so it boosts it. And the problem with boosts instead of cutting peaks is that you're basically forcing the drivers to reproduce frequencies it's weaker at and you get more driver distortion.

Neutralizer for Android has less control bands, but it runs the test tone with manual boost or cut so you determine how well you should be able to hear each test tone. It has a wide swath in the midrange though, which means that if your'e trying to correct the 2000hz dip in the HE400i, it will end up boosting the low peak at 3500hz too much.

By contrast if you use Neutron (or EQ APO) you can select the Q factor along with the gain and center freq you could put a relatively narrow boost centered at just under 2000hz and then cut at 3500hz just to counter the effect (though if you tried to flatten it you'd end up offsetting the initial boost)

I'm excited by what is happening in this space, and I'm looking forward to more solutions like this. Ideally, digital correction for headphones should be an integrated part of the playback chain, with all headphones either coming with (ideally individual) measurements to use in the correction, or in the case of integrated amping with the correction built in.

There was an IOS player app before that instead of having an EQ tweakable for the user they have a database of correction profiles for many headphones, this way the correction can be more pinpoint in flattening the response. Unfortunately that app eventually died out and no updates have happened in years. They didn't even patch it to work on an iPad size screen.

 

[gzost]

Neutralizer for Android has less control bands, but it runs the test tone with manual boost or cut so you determine how well you should be able to hear each test tone. It has a wide swath in the midrange though, which means that if your'e trying to correct the 2000hz dip in the HE400i, it will end up boosting the low peak at 3500hz too much."

I've tried Neutralizer, but also found the number of bands too limited. Simple, intuitive UI though.

I suspect that on Android, if you want system-wide correction, the best you can do is add a nice UI to the integrated EQ, which appears quite limited. There does not appear to be a plug-in architecture. All the EQ apps I've tried have just been skins of some sort for the the same bands, bass bost etc.